Rigel Pharma (NASDAQ: RIGL) shares are pulling back following a 49 percent gain on Tuesday. The stock is down around 4 percent.

Yesterday, Rigel announced that fostamatinib, its oral spleen tyrosine kinase (SYK) inhibitor, met the primary endpoint in the first of two double-blind studies in the FIT Phase 3 clinical program for the treatment of adult chronic/persistent immune thrombocytopenia (ITP).